Tuesday 16 April 2019

OUGD603 - Research Brief - The Black Hole

OUGD603 

 Research Brief
The Black Hole

Bibliography
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3478626/
https://www.nature.com/news/teaching-load-could-put-female-scientists-at-career-disadvantage-1.21839
https://www.particlesforjustice.org/

 This week the first ever image of a black hole was captured by scientists. 

 The black hole is located in a galaxy called Messier 87. The image is not a photograph but an image created by the Event Horizon Telescope (EHT) project. Using a network of eight ground-based telescopes across the world, the EHT collected data to produce the image.

 We are unable to see the black hole itself as this is impossible as light cannot escape from it. The image actually shows the event horizon. The EHT was also observing a black hole located at the centre of the Milky Way but was unable to produce an image. While Messier 87 is further away, it was easier to observe, due to its larger size.

Event horizon
The golden ring is the event horizon, the moment an object approaching a black hole reaches a point of no return, unable to escape its gravitational pull. Objects that pass into the event horizon are thought to go through spaghettification, a process, first described by Stephen Hawking, in which they will be stretched out like a piece of pasta by gravitational forces.

The hole in the centre

Heino Falcke, professor of radio astronomy and astroparticle physics at Radboud University in Nijmegen, and chair of the EHT science council, says the image shows a silhouette of the hole against the surrounding glow of the event horizon, all of the matter being pulled into the hole. At the centre of the black hole is a gravitational singularity, where all matter is crushed into an infinitely small space.

How big is the black hole?

The black hole lies 55m light years away from us. It is around 100bn km wide, larger than the entire solar system and 6.5bn times the mass of our sun.
Tim Adams - The Guardian
As TS Eliot observed in his meditation on Einstein’s space-time continuum in Burnt Norton, “humankind cannot bear too much reality”. The science proves the black hole is way beyond most of our understanding, but the evidence now in front of our eyes reminds us that the simplest principle of the universe remains the hardest for us to grasp: it’s not about us.

Black Holes
Albert Einstein wrote a paper in 1939 which attempted to reject the notion of black holes that his theory of general relativity and gravity seemed to predict. "the essential results of this investigation, is a clear understanding as to why the 'Schwarzschild singularities' do not exist in physical reality.' 
Schwarzschild singularities, later known as 'black holes' describes objects that are so massive and compact that time disappears and space becomes infinite. The same year Einstein sought to discount the existence of Black Holes, J. Robert Oppenheimer and his student Hartland S. Snyder used Einstein's theory of relativity to show how black holes could form. 

Black holes ( AQA A CGP) 
If the core of the star is more than three times the suns mass, the core will contract until neutrons are formed, but now the gravitational force on the core is greater - the neutrons can't withstand the gravitational force. There is nothing left to stop the core collapsing to an infinitely dense point. 
At that point, the laws of physics break down completely.
The escape velocity is the velocity that an object would need to travel at to have enough kinetic energy to escape a gravitational field. When a massive star collapses into an infinitely dense point, a region around it has such a strong gravitational field that it becomes a black hole - an object whose escape velocity is greater than the speed of light, c. If you enter this region, there is absolutely no escape - not even light can escape. 
The boundary of the region around the infinitely dense point in which the escape velocity is greater than c is called the event horizon. It is the distance at which the escape velocity is equal to c (the speed of light), so the light has just enough kinetic energy to overcome the gravitational pull. 
The event horizon of a black hole is called Schwarzschild radius - it is thought of being the radius of a black hole. Inside the Schwarzschild radius, everything, including light, can do nothing but travel further into the black hole. 
Astronomers now believe that there is a supermassive black hole at the centre of every galaxy. As they consume stars close to them, they produce intense radiation, making the centre of the galaxies very bright.

Special Relativity
Frames of reference - just a  space or system of coordinates that we decide to use to describe the position of an object. (A set of coordinates) 
An inertial frame of reference is one that obeys Newton's first law (an object won't accelerate unless acted on by an external force) Rotating or accelerating reference frames arent inertial. 
Einstein's theory of relativity only works in inertial frames and is based on two assumptions:
1) physical laws have the same form in all inertial frames
2) the speed of light(c) in free space is invariant. 
Summary: It explains the behaviour of things that move very very fast - as in, a significant fraction of the speed of light - where Newtonian physics don't always apply. It's called special relativity because it only applies in specific situations where the different frames of reference aren't accelerating (see assumptions).

A method to image black holes
Researchers have developed a new algorithm that astronomers could use to produce the first image of a black hole. The algorithm would stitch together data from radio telescopes scattered around the world. Radiowaves are used. They have long wavelengths so require large antenna dishes. Black holes are very, very far away and very compact. To take an image of something so small would require a telescope with a diameter of 10,000km, which is not practical because the Earths diameter is only 13,000km. The solution adopted by the Event Horizon Telescope team project is to coordinate measurements performed by radio telescopes at widely divergent locations. Katie Bouman has created an algorithm that fills the gaps left by the telescopes. The algorithm is named CHIRP - continuous high-resolution image reconstruction using patch priors. 


Katie Bouman
The post-doctoral fellow at MIT whose algorithm led to an image of a supermassive black hole. Katie Bouman was a PhD student in computer science and artificial intelligence at the Massachusetts Institute of Technology (MIT) when, three years ago, she led the creation of an algorithm that would eventually lead to an image of a supermassive black hole at the heart of the Messier 87 galaxy, some 55m light years from Earth, being captured for the first time. Bouman was among a team of 200 researchers who contributed to the breakthrough. The data used to piece together the image was captured by the Event Horizon Telescope (EHT), a network of eight radio telescopes spanning locations from Antarctica to Spain and Chile. Bouman’s role, when she joined the team working on the project six years ago as a 23-year-old junior researcher, was to help build an algorithm which could construct the masses of astronomical data collected by the telescope into a single coherent image. Once the algorithm had been built, Bouman worked with dozens of EHT researchers for a further two years developing and testing how the imaging of the black hole could be designed.
Using imaging algorithms like Bouman's, researchers created three scripted code pipelines to piece together the picture.
"We developed ways to generate synthetic data and used different algorithms and tested blindly to see if we can recover an image," she told CNN.

"We didn't want to just develop one algorithm. We wanted to develop many different algorithms that all have different assumptions built into them. If all of them recover the same general structure, then that builds your confidence."
The result? A groundbreaking image of a lopsided, ring-like structure that Albert Einstein predicted more than a century ago in his theory of general relativity. In fact, the researchers had generated several photos and they all looked the same. The image of the black hole presented on Wednesday was not from any one method, but all the images from different algorithms that were blurred together.

Effects of social media
Trolls and Katie Bouman 
Female scientists have claimed that social media is facilitating "brutal" and "sickening" misogyny after trolls repeatedly targeted the woman whose work contributed to the first picture of a black hole in space. Dr Katie Bouman was targeted this week by internet trolls, who said she was falsely claiming ownership of the black hole project and attributed the breakthrough to her male colleague, computer scientist Andrew Chael.

The tweet shown below, posted by MIT may infer that Bouman and her algorithm alone led to the creation of the image.
They have since tweeted, emphasising that Bouman and her team were part of a collaboration. For some people, it was easier to relate to one delighted face than 200. But in fact, 200 scientists, 60 institutions, 18 countries and 6 continents made up the Event Horizon Telescope Collaboration. Bouman wrote in a Facebook post: 'No one algorithm or person made this image, it required the amazing talent of scientists from around the globe and years of hard work to develop the instruments, data processing, image methods, and analysis techniques that were necessary to pull off this seemingly impossible feat. It has been truly an honour, and I am so lucky to have had the opportunity to work with you all.'
People began going over her work to see how much she had really contributed to the project. Trolls focused on her colleague, Andrew Chael, who was listed on GitHub as the primary developer for one of the algorithms that revealed the black hole and started circulating his picture instead. 
Chael responded:
Chael - "it was clearly started by people who were upset that a woman had become the face of this story and decided 'I'm going to find someone who reflects my narrative instead.'" 
This isn't just an online trend. Women in science are cited less than their male colleagues. They have a harder time getting their work published in notable journals. They are likely paid less than their peers (a 2013 study found that women working in physics and astronomy were paid 40% less than men.) and they are more likely to face workplace harassment. 

Female Authors get fewer citations in astronomy
A study by Nature Astronomy reports that papers with female authors receive 10% fewer citations than comparable papers with male authors. 'citations from publications are currency - that is your net worth in academia.' says Anna Kaatz, director of computational sciences at the Center for Women’s Health Research at the University of Wisconsin in Madison. The lower your citings, the lower status you are as a scientist, regardless of how meritorious your work is. This can have a negative effect on job prospects and career trajectory. Papers from men still receive 6% more citings than papers from women. Based on this analysis, gender bias, not paper quality - appears to be the most likely explanation for the citation gap. There is evidence that women receive lower quality mentoring, and female faculty members tend to be assigned service and teaching responsibilities that can take away from their time spent on research. 

Fewer than 25% first authors in the journals Nature and Science were female. even though around 40% of students that study for postdocs in the same field are women. 


The Gender Gap
According to the US National Science Foundation, women earn about half the doctorates in science and engineering in the US but comprise only 21% of full science professors and 5% of full engineer professors. On average they earn just 82% of what male scientists make. 
A disproportionate fraction of qualifies women drops out of science careers in the very early stages. Many experts say that a big factor driving this trend is a lack of role models in the uper divisions of scsdemia, which have been slow to change. The royal society of Chemistry has found that female cheistry students are more likely than males to express low self-confidence and to report feeling dissatisfication with mentorship. In Biology, women comprise 36% of assistant professors and only 27% of tenure candidates in 2010. (US National Research Council). 
Many of the UK chemistry students viewed research as an all-consuming endeavour that was incompatible with raising a family. Family choices seem to weigh more heavily on the career goals of women. 

The plan to have children in the future, or already have them, is responsible for an enormous drop off in the women who apply for tenure-track jobs. 

Gender discrimination
showed that science faculty members of both sexes exhibit unconscious biases against women. Handelsman's group asked 127 professors of biology, chemistry and physics at 6 US universities to evaluate the CVs of two fictitious college students for a job as a laboratory manager. The professors said they would offer the student named Jennifer US$3,730 less per year than the one named John, even though the CVs were identical. The scientists also reported a greater willingness to mentor John than Jennifer. 
Her findings match well with the results of a survey7 done in 2010 by the American Association for the Advancement of Science. Of the 1,300 or so people who responded, 52% of women said that they had encountered gender bias during their careers, compared with just 2% of men.

Pay Gap
In the European Union, female scientists earned on average between 25% and 40% less than male scientists in the public sector in 2006.
Although the average pay gap is smaller in the United States, the disparity is particularly large in physics and astronomy, where women earn 40% less than men.
For young academic scientists, however, those differences may be fading. The National Research Council found an 8% pay gap at the level of full science and engineering professors but no significant differences among junior faculty members.

 Sexual Harassment in the sciences
Sexual harassment is pervasive throughout academic science in the United States, driving talented researchers out of the field and harming others’ careers, finds a report from the US National Academies of Sciences, Engineering, and Medicine in Washington DC. The analysis concludes that policies to fight the problem are ineffective because they are set up to protect institutions, not victims.
The most common type of sexual harassment is gender harassment, the report finds. Such behaviour conveys the impression that women do not belong in the workplace or do not merit respect. 

 Almost 60 societies in science, technology, engineering, mathematics and medicine (STEMM) have formed a consortium to tackle sexual harassment. The consortium has begun to collect model policies, law guidance as well as tools to prevent and respond to sexual and gender harassment in STEMM.

 Research Grants and Gender Bias
Data shows 90% of engineering and physical sciences funding in UK goes to male-led projects.
In 2016-17, fewer than 7% of all research grants went to teams led by women – the lowest proportion for 10 years. Even when women do successfully apply for funding, they are awarded less money than their male colleagues. In the past five years, more funding has consistently been granted to men and last year the average size of grant to women was less than 40% of what their male counterparts received. The data also showed that from 2007-08 to 2015-16 women were underrepresented on peer review panels that determine who gets a grant and how much, taking fewer than one in five of the seats. As recently as 2013-14 women were outnumbered nine to one in panel meetings and though the figures have improved, today women still make up fewer than a third of review panel members. Women comprise 17% of the engineering and physical sciences academic community, and those working in the field say their underrepresentation in successful research funding bids is just one symptom of pervasive gender inequality.
According to EPSRC figures, in 2016-17 the total grant value awarded to projects with male principal investigators was a little over £944m, compared with the £69m awarded to female principal investigators.
“The knock-on effect of not winning funding can also lead to an increased teaching load on women in male-dominated departments where men are winning grants and buying themselves out of teaching and/or admin duties, thereby further aggravating the problem.”
“Women currently represent only 14% of the Stem [science, technology, engineering and mathematics] workforce and when women struggle in their careers, through lack of support, the absence of peers and systemic bias against funding opportunities, it can deter women from entering or staying within the field.
“Celebrating, encouraging and supporting women’s contributions to science and other Stem subjects is the only real way to encourage future generations to put themselves forward more readily.”
Gender Bias
Despite efforts to recruit and retain more women, a stark gender disparity persists within academic science. Abundant research has demonstrated gender bias in many demographic groups, but has yet to experimentally investigate whether science faculty exhibit a bias against female students that could contribute to the gender disparity in academic science. In a randomized double-blind study (n = 127), science faculty from research-intensive universities rated the application materials of a student—who was randomly assigned either a male or female name—for a laboratory manager position. Faculty participants rated the male applicant as significantly more competent and hireable than the (identical) female applicant. These participants also selected a higher starting salary and offered more career mentoring to the male applicant. The gender of the faculty participants did not affect responses, such that female and male faculty were equally likely to exhibit bias against the female student.

 Female teaching load
Male scientists in the United Kingdom report teaching less than their female counterparts, while women and minorities tend to feel disadvantaged in their careers.
Female academics report spending more time on teaching and public-engagement tasks, and less time on research, than their male counterparts, according to a survey of UK university staff in science-based subjects.
If men spend more time on research, this could improve their career prospects when research productivity is used as a proxy for scientific merit, “which is nearly always”, says Pollitzer. It could also help to explain why many bibliometric studies have reported lower research productivity for women than for men, she adds.
In interviews following up on the survey, academics suggested that women’s increased focus on teaching and public engagement might put them at a disadvantage, not only because these activities take time away from research, but also because they carry less academic prestige.
Significant differences emerged in men and women’s perceptions of how much support and encouragement they receive. Women were more likely to report that men have better access to professional development, such as mentoring, than women have, and that men receive more invitations to conferences. Men tended to see no such advantage for themselves.

 Alessandro Strumia
Strumia was suspended from CERN after his lecture explaining why the physics sector is mainly male based. He argued that its about inherent ability, not discrimination. The 'data' he uses to explain these claims are based on the number of women n physics right now, and how often paper written by women are cited. In the U.S., just 20 percent of undergraduate and doctoral degrees are awarded to women. One of Strumia's slides read 'physics was invented and built by men.' 

 The talk took place on 28th September 2018. In this talk, he argued that the primary explanation for the discrepancies between men and women in theoretical physics is that women are inherently less capable.

 Thoughts from the website Particles for Justice
The question of discrimination based on ascribed identity is a moral one, and we write to affirm that discrimination is not a welcome feature of our field, however pervasive it may be. It is clear that our social environment disparately affects the participation of people with ascribed identities that have been traditionally marginalized, and the fields of women’s and gender studies, science and society studies, physics education research, anthropology, sociology, philosophy, and Black studies have had much to say over the years about how this marginalization operates. The thin veneer of scientific rigour with which Strumia’s talk began was followed by open discrimination and personal attacks, which we condemn unconditionally.
Secondly, we write to strongly express our view that the science case presented by Strumia was fundamentally unsound. It is clear to all of us that Strumia is not an expert on these topics and is misusing his physics credentials to put himself forward as one. Furthermore, those among us who are familiar with the relevant literature know that Strumia's conclusions are in stark disagreement with those of experts.
Strumia argues that since women are more well-represented in theoretical physics in countries where discrimination is more brazenly institutionalized, this shows that their low representation in physics has nothing to do with discrimination. This claim ignores cultural differences, and also the possibility that women in such countries have fewer career options outside of academia. Without controlling for such effects, any attempt to draw conclusions is meaningless.
Strumia argues that since the most cited papers are disproportionately by men, this gives evidence that men are intrinsically better at physics. In between intrinsic ability and citation counting however, there is the huge and complicated process of how physicists are raised, trained, hired, and perceived. Even at the professorial level, discrimination can still play an important role (such as e.g. the imbalance in telescope time awarded to female researchers (5)). Without a thorough understanding of these processes, it is impossible to conclude anything about people’s innate abilities.
Strumia argues that Marie Curie's Nobel prize is evidence against discrimination. Lauding one outstanding individual does not exculpate anyone from oppressing thousands of others. Further, it should be noted that Marie Curie faced both xenophobic and sexist resistance to her work both during her research and during the process of receiving the Nobel Prize. Her success, in spite of this resistance, is heroic and admirable, and not an example of being welcomed with open arms by the community as Strumia suggests. Moreover, there are at least four women whose work is relevant for particle physics who are widely viewed as having deserved the Nobel prize but who did not receive it, in some cases even though their male colleagues did: Chien-Shiung Wu, Vera Rubin, Lise Meitner, and Jocelyn Bell Burnell. While we are pleased to see Prof. Strickland's accomplishments recognized this year, a gap of 55 years since the last woman won the Nobel Prize in Physics does not suggest that women in our field face no external obstacles to success. Such well-known cases were accomplishments of women were not formally acknowledged suggest that similar omissions may be occurring at all levels, and raise another possible reason for the differential in citations discussed previously.
Strumia argues that it is actually men who experience discrimination since they are more likely to serve in wars and be used as forced labour. While many talented people of all genders still face barriers due to war and conflict, these concerns are not part of the experience of the majority of white male physicists born and raised in Europe or North America in the current era. He also misquotes the Istanbul convention as saying that men cannot be discriminated against when the actual text is that "special measures that are necessary to prevent and protect women from gender‐based violence shall not be considered discrimination under the terms of this Convention." (Istanbul Convention, Chapter 1, Article 4.4)
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